If you haven't read Cat and the Dreamer, you should. It is very beautifully written, with a main character who will pull at your heartstrings.
I don't remember having an imaginary friend, but I had four siblings so I had plenty of people to play with and blame stuff on growing up. :) However, when I had my third kid, my son ended up developing an imaginary friend. He called him his brother, Jack.
I think it was because the others were both girls. (As is child #4, so he's still the only boy.) I'm guessing he was jealous that my oldest got a little sister to play with, but he didn't have a brother. So he made one up.
Jack was talked about a lot that year. Johnny would tell us about all the super fun exciting things he and Jack were doing. (And yes, I think it's funny that the name he picked for his friend is a nickname for his own name.)
There were times it got a bit awkward and I would feel the need to explain to people what was going on. Like when he told our EFCE teacher that him and his dad had spent the weekend at his brother's house.
"Um yeah," I told her, "it's an imaginary friend. My husband does not, in fact, have another family somewhere else."
Have a great weekend everyone!
And thanks Kyra and Annalisa for hosting!